"My only direct relative is a half-sister who lives in California," he said. "She is opposed to me being a dog and hates the concept. She seems to think I am crazy."
Not all people think he is nuts. Lois Achchammer of Winterville, Ohio, has known Matthews for years as "Boomer." He was a friend of her son, Mike, and they built short-wave radios together.
"He's a real nice guy," said the 68-year-old retiree. "When I first met him I didn't know it was because he was a dog, I thought it was a nickname."
"He's very quiet, very reserved and very polite and well-mannered," said Achhammer. "I couldn't say anything bad about him. They say there is a fine line between insanity and genius and I think he's on that line. He's a very intelligent young man."
Matthews is so dogged about having his name changed to Boomer that in 2010, he petitioned the court, but was denied. Today, he hopes to try again and tells his story to prove to the judge that he is not doing it for fraudulent reasons.
"Going public with being a dog isn't just about the name change," said Matthews. "That's only the most recent thing that I'm focusing on, because really, being a dog is about everything -- it's the way that I live."
Matthews said he has no idea why he is so drawn to being a dog and admits it was hard being different as he was growing up. "I got flak for it," he said. "My parents didn't like it. Earlier on, they saw it as a kid thing and they laughed. But at a certain point in time there are adult expectations and they want you to go off to work and date. Society wants to straighten you out."
In school, the other children teased Matthews and when he was still acting like a dog in high school he was sent to a "special school" for teens who have social and emotional problems.
Matthew has never dated and has no interest in marriage or children. "I have good friends and I substitute friendship for anything closer than that," he said.
He also belongs to a group called "furries" – people who dress like animals and meet at clubs around the world. "I have a group of fans, people who perform as mascots – they are a nerdy group like trekkies and like dog play," he said.
Julia Ramos-Grenier, who practices forensic neuropsychology in Tucson, Ariz., and has not treated Matthews, said she had some concern over what may be a compulsion to behave as a dog.
"This is an unusual kind of thing and there isn't really a lot of research to give you some idea what is going on psychologically in the mind and the brain," she said. "The one thing I worry about is it sounds like he is alone and therefore that starts to affect his personal life."
In compulsive behavior, a person "needs to do it and feels better when they do it," said Ramos-Grenier. "It releases tension or anxiety and is something positive for them. The behavior starts to be a problem when it goes over the line."
Like Matthews, she said she has no idea why he developed this compulsion to be a dog.
"Maybe it was his natural make-up when he was developing his personality or it could have been a traumatic event or an association with something pleasurable," she said. "Maybe he got a lot of reinforcement and a loving kind response from dogs that he didn't get from other people."
But Matthews insists there is nothing wrong with him: "I see it as a lifestyle. I just live differently."
And he was thrilled to be the subject of an interview by ABCNews.com, writing to this reporter, "Woof, woof! Good barking with you today."